Abstract: Our investigations into the early irreversible progression in hypertrophic cardiomyopathy and the lack of effective treatments has led us to concentrate on the coronary microvasculature. Clinical studies have been characterizing the deleterious vascular alterations occurring in the disorder, but further investigations into the underlying mechanisms behind this relationship have been minimal. The experiments proposed within the proposal will begin to answer the role perfusion and vascular dysfunction play in the progression of hypertrophic cardiomyopathy. Given the mechanical and energetic deficiencies in the disorder, it is likely that they impede physiological coronary flow that drives remodeling of vessels. These relationships and influencing factors will be looked more closely into. The endothelial dysfunction within the myocardium is expected to have a substitution of the primary vasodilator nitric oxide to ROS signaling as is stereotypical of vascular dysfunction. We will therefore make efforts to understand this switch between vasoactive molecules and its impact on coronary alterations. We will lastly attempt to modify the endothelial function in hypertrophic cardiomyopathy with an sphingosine-1-phosphate analog, FTY720, to prevent the irreversible progression established early on.